An immunoassay is a well known laboratory method used to determine the amount of an analyte in a sample such as plasma or urine. It is based on the interaction of antibodies with antigens, and because of the degree of selectivity for the analyte (either antigen or antibody), an immunoassay can be used to quantitatively determine very low concentrations of drugs, hormones, polypeptides, or other compounds found in a test sample. For many years, trained laboratory technicians performed immunoassays by hand.
Various chromatographic immunoassay techniques have been available for many years. One common aspect of known devices, particularly in the lateral flow technology, is that the assay is read visually, that is, by means of one or more optically readable lines on a test strip, typically held in a carrier, which may have various configurations. One end of the test strip is exposed to the sample, normally a body fluid of some type, being tested for the particular target analytes of interest. It is known that particular analytes are indicative of particular biological, environmental, and biohazard conditions, among others. For example, urine may be tested for pregnancy or ovulation and if the target analytes are present, the test is positive. Body fluids may be tested for the presence of other analytes indicative of biological conditions or they may be indicative of the presence of substances, such as drugs. Another example would be for testing water for contaminates. Examples of lateral flow assay methods and apparatus, where the reading is conducted optically, are shown in U.S. Pat. Nos. 5,591,645; 5,798,273; 5,622,871; 5,602,040; 5,714,389; 5,879,951; 4,632,901; and 5,958,790.
Recently, many companies have begun producing automated immunoassay analyzers. Automating the immunoassay procedures has been difficult because of the large number of steps that need to be performed. For example, a sample is mixed with a reagent and a solid support having a bound antigen or antibody, the sample is incubated such that the corresponding antigen or antibody in the sample and a labelled antigen or antibody provided in the reagent can be bound to the antigen or antibody on the solid support, then the solid support is thoroughly washed and the label (fluorescent, radioactive, chemiluminescent, or the like) is detected by an appropriate mechanism, and finally the analyte of interest (antigen or antibody) is quantified from the detected label.
One of the problems with reading of Lateral flow cassettes and also other similar cassettes is the lack of a true general reader. All of the readers on the market today are designed for a group of cassettes with similar properties. A consequence is that the user needs to use different instruments with different shape, user interface and connection to printer and journal systems. The lack of a general instrument limits the possibility to use low cost measurement cassettes.
A general instrument must be able to process cassettes of different shapes and colours. A scanner or camera-based system can be able to read cassettes of different shape as long as it is possible to locate the cassette on a scanner plate or another suitable place for a capturing a camera image. The contrast between the cassette and the background can be high or low dependent of the colour of the cassette and the colour of the background. The image can also contain shadows at the edge of the cassette. The image can be out of focus, or be distorted. A scanner plate background is normally either black or white, but when scanning with the scanner lid lifted up (the cassette is not completely flat), the image can also contain ambient lightning from light sources outside the scanner. The background when capturing a camera image can be anything the user finds suitable. Ambient lightning can also be difficult to control when capturing a camera image of a device.
Use of barcodes is becoming more widespread; including use of barcodes for identifying many different types of things, including, but not limited to commercial goods, such as groceries, product packages of various types, printed reading material. A barcode typically assigns a unique identifier to a particular commodity.
A barcode is a graphic identifier used to encode a set of digits or characters. A barcode comprises a series of bars and spaces, which may have different widths according to various encoding rules, such as the standard commodity barcode EAN13 barcode specification.
In the bio-medical field a barcode has been described as to convey specific information about a patient, including clinical history and as a unique identifier of the patient sample, in addition to the categorization of the assay being conducted on the patient sample as well as for tracing and control purposes.
From the abovementioned, it will be appreciated that there remains a need in the art for a general, simple, effective means to locate, calibrate and identify biological test devices.